This invention relates to the fabrication of microminiature devices and, more particularly, to an automated, high-speed electron beam apparatus and method for making such devices.
It has long been known that the high-resolution and excellent depth-of-focus capabilities of an electron beam make it a practical tool for inclusion in an automated system for making microminiature electronic devices. The electron beam is controlled in a highly accurate and high-speed manner to expose an electron-resist-coated material as a step in the fabrication of extremely small and precise low-cost integrated circuits.
Although an electron beam can be deflected and blanked in a high-speed manner the area over which the beam is capable of being deflected is relatively small. A basic problem presented, therefore, is how to accommodate this small-area scan field to the rapid and efficient exposure of relatively large resist-coated areas such as desirable with increasingly larger semiconductor wafers. In addition to larger areas to be exposed, larger densities of circuit elements are desired on semiconductor. The trend in the industry has been a greater number of circuits per unit of area and a tendency towards smaller and smaller circuits. In this manner, it becomes increasingly possible to integrate an entire system or subsystem on a relatively few number of semiconductor chips.
In order to accommodate the greater density of circuits, the electron beam system is required to process a much greater amount of data. Without increased exposure rates and without improved techniques, the time required to process the data and make exposures becomes excessive. A basic problem, therefore, is presented as to how to increase the data rate of electron beam systems.
In accordance with the above background of the invention, it is an object of the present invention to provide an improved electron beam apparatus and method which is capable of greater data rates and hence is capable of a more rapid and more efficient exposure of high-density, resistcoated areas used in the manufacture of integrated circuit devices.